边缘牙齿形碟盘破碎煤岩的力学机理及其模型

摘要

为提高煤岩的破碎效率与破碎能力,介绍一种具有楔劈特征的边缘牙齿形碟盘轴向振动与径向切削破碎煤岩的方法.采用抗压、抗剪等不同阶段主导作用相结合的力学方法,分析牙齿宽度对煤岩在挤压、压裂和破碎各阶段,以及由碟盘楔面倾角楔劈作用下大块煤岩崩落各过程的力学关系;运用复合作用效应的叠加原理,建立了各工况下破碎煤岩的力学模型,揭示边缘牙齿碟盘破碎煤岩的力学机理.研究表明:在煤岩由初期压馈小岩坑的形成、裂纹的产生、贯通直至由碟盘楔面楔劈作用下大块煤岩崩落过程力学描述的基础上,得到了碟盘径向与轴向载荷与碟盘结构参数,以及煤岩破碎相关联参数的数学模型;得出复合轴向向上运动方式有利于破碎煤岩依据;碟盘刀具径向与轴向载荷均随切削厚度的增加而增加,单切削作用时理论模型径向和轴向与数值模拟计算结果相差11％和4％,复合作用时理论模型径向和轴向与数值模拟计算结果相差3％和18％,验证了理论计算与数值模拟其载荷随破碎煤岩厚度等参数的变化规律具有一致性.该研究为高效率、高破碎能力的破碎机构研制提供了理论参考.%In order to improve the crushing efficiency and rock breaking ability of coal and rock,a method of axial vibration and radial cutting of coal rock with wedge is proposed.Using the mechanical method of combination of compression,shear which are dominated at different stages,the paper analyzes the mechanical relationships of disc plate single tooth width in the extrusion,fracturing and fragmentation stages,as well as the disk with wedge to large lump coal rock collapse each process.Based on the superposition principle of compound effects,a mechanical model under various working conditions is built to reveal the mechanical mechanism of the broken coal rock on the edge of the tooth disc.The research shows that based on the mathematical description of the process of the formation of small pits,the generation of cracks and caving,through the process of caving of large chunks under the wedge,the mathematical model of radial and axial load is built with the parameters of the disc structure and the rock breaking parameters.The axial upward movement of the composite axis is favorable to the fracture of coal rock.The radial and axial load of disc cutter increases with the increase of cutting thickness.The radial and axial loads of the disc are 11％ and 4％ difference between the numerical simulated results.And the radial and axial loads of the disc are 3％ and 18％ when the composite action cutting is performed.The variation law of the parameters such as the thickness of the rock is consistent with the theoretical calculation and numerical simulation.The study provides a theoretical reference for the development of high efficiency and high crushing capacity.